The JPC ROM for the HP-71B


(From an Educalc catalog)

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JPC ROM History

The JPC ROM is a great extension of the HP-71B system. It was developed between 1986 and 1989 by the PPC-Paris User Club. After the Club finally collapsed, a few individuals continued to work on it. Here are the main milestones:

   1985: .. first LEX files in JPC Journal           -
   1986: .. First JPC LEX                            |  PPC
   1987: .. First JPC ROM                            |   -
   1988: .. JPC ROM ver. D ---->------               | Paris
   1989: .. JPC ROM ver. E           |               -
                 |                   |
                 |                   v              
   1992: ....... | ............ JPC ROM ver. X     (R. Rosenbaum)
                 |                   |
                 |  -----------<------
                 |  |
                 v  v
   2007: .. JPC ROM ver. F  The JPC ROM Legacy !   (compiled by J-F Garnier)


JPC ROM Versions

A list of JPC ROM features and bug fixes for versions A to F, is described in this JPC ROM version history.
The unofficial version X is described in this

Binary ROM images (ready for Emu71, or for standalone EPROM programmer)


* The JPC LEX version X and the documentation were made available to all by Gene Wright and Andy Delano through the MoHPC forum on March 2003. Many thanks to both of them.
** Claude Marcoin provided me the JPC LEX version E on April 2006. Claude also scanned the supplement manual pages for version E. Un grand merci, Claude!

JPC ROM Source Files

I'm especially proud to present the rebuilt source files for the JPC ROM. It was a long project for me, For years, I looked for the original source files (the ones that were used on a HP Integral PC - a "portable" HP-UX machine - to create the JPC ROM), and I finally came to the conclusion that this material was definitively lost.

To recreate the JPC ROM source files, I collected and edited files, sometimes from paper copy, from various sources (Swap Disks, JPC Journals, personal archives, private communications, JPC LEX disassembly from Rodger Rosenbaum) during the year 2005, and I finally successfully assembled the exact JPC ROM version X on May 2006.

JPC ROM Version X:

Special thanks to Rodger Rosenbaum for providing me his source file (actually a disassembly of the JPC LEX). I used it as a source for the few modules that have never been published in source form, and I also attempted to document the changes made in version X.

JPC ROM Version E:

Standalone XEDIT LEX:

Although XEDIT was included in the JPC ROM E, it was originally published as a standalone LEX in the JPC journal, and it may be more convenient for HP-71B users that don't have large RAM space.
The XEDIT LEX provides two text editors:
- TEDIT is fully compatible with the EDTEXT editor from HP found in the Forth/Assembler ROM,
- XEDIT is an enhanced version with Unix-like generic string support for search and replace operations.
Both versions are written in machine code for fast operation.
Note that the source of the xaux and find modules that were not released at the time have been rebuilt from a disassembly of the JPC ROM E.


NEW (Dec. 2022): Standalone "GRAPHIC module" ROM:

In the same way as XEDIT, the graphic functions included in the JPC ROM E were originally available as a standalone LEX, the "GRAPHIC module" for the HP-71B.
A binary image of "GRAPHIC module" ROM, dated June 1988 has recently been recovered (Dec. 2022):

Version (VER$) is "GRPH:A RSTR:B".
There are no source files available yet, but they are likely close to the files included in the JPC LEX E and may be rebuilt later.





The JPC ROM Legacy : Version F - Updated to F05 Feb.2017

This JPC ROM version is special in the sense that I built it about 18 years after the last official JPC ROM from PPC Paris (version E, 1989). It was actually the final goal of my JPC source file project: be able to easily modify and possibly extend the historic versions. With this version F, I mainly merged all the fixes and improvements of version X with the version E, but didn't include the editor and the graphic module of version E in order to fit into a 32kB module (actually, some code packing made it a bit less than 26kB long). I also added a few changes, see the JPC ROM version history.


The F05 update fixes a major bug introduced in version X and reported only on beginning of 2017 on the MoHPC forum.

Contributions are still welcome! Please contact me if you have any suggestions, bug fixes or enhancements to propose!


If you want to modify and re-assemble the JPC LEX, you may need the following tools:

You can also refer to this updated Entry Point List:



If you have more information on the JPC ROM versions, if you participated to the project or made improvements to it, please contact me:

J-F Garnier, 2022